#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include<string.h>
int main()
{
    char  arr[500] = { 0 };
    int n = 0;
    int count = 0;

    int i = 0;
    int j = 0;

    scanf("%s", arr);
    n = (int)strlen(arr);

    for (i = 0; i < n; i++)
    {
        if ((arr[i] <= 127) && (arr[i] >= 0) && (arr[i] != '\n'))
        {
            count++;
        }

        for (j = i + 1; j < n; j++)
        {
            if (arr[i] == arr[j])
            {
                count--;
                break;
            }
        }
    }
    printf("%d", count);

    return 0;
}